The present invention relates to a data recording apparatus, and more particularly to a data recording apparatus for recording data on a recording medium, such as a CD-R, a CD-RW, a DVD-R, or a DVD-RW.
Optical disk recording media, such as an LD (Laser Disk), a CD-ROM (Compact Disk Read Only Memory), an MD (Minidisk), and a PD (Phase-change Disk), are essential media for recording multimedia information. A DVD (Digital Versatile Disk), which has a storage capacity approximately 7.5 times as large as that of the CD-ROM, is also used for the same purpose. With such an increase in storage capacity of the recording media, a higher recording speed is required of a data recording apparatus. Further, as portable personal computers become more popular, there is an increasing demand for a data recording apparatus that is even more compact in size and consumes less electric power.
Methods of recording data on an optical disk employed by the data recording apparatus include the Constant Linear Velocity (CLV) method, the Zone Constant Linear Velocity (ZCLV) method, and the Constant Angular Velocity (CAV) method.
The CLV method employs a data recording format shown in FIG. 1. More specifically, in this method, units of data are recorded in respective sectors of each track T of a disk. Each sector has an address area A1 and a data area A2, and each sector has a fixed length irrespective of the radial position of the sector on the disk.
In the CLV method, the data recording apparatus controls the rotational speed of the disk such that each track T on the disk corresponding in position to a pickup device of the system is rotated at a constant linear speed, as shown in FIG. 2(a). The data recording apparatus holds the data rate (i.e. the frequency of recording data) at a constant level regardless of a position on the disk, as shown in FIG. 2(b). The term xe2x80x9cdata ratexe2x80x9d refers to the amount of data recorded on a disk per unit time. Through the control described above, the length of each sector is constant irrespective of the radial position of the sector on the disk, as shown in FIG. 2(c).
The ZCLV method employs a data recording format shown in FIG. 3. More specifically, a plurality of zones Z are arranged radially, and sectors of tracks T in an outer zone Z are longer than sectors of tracks T in an inner zone Z. Within each zone Z, the length of each sector varies at a predetermined rate from one track to another. To this end, the sectors of all the tracks T in the zone are radially aligned and arranged in a radial pattern.
In the ZCLV method, the data recording apparatus performs zone-by-zone stepwise adjustment of the rotational speed of the disk based on the position of the pickup device, such that the plurality of tracks T within an identical zone Z are rotated at a constant linear speed as shown in FIG. 4(a). The data recording apparatus holds the data rate at a constant level regardless of the radial position of the pickup device, as shown in FIG. 4(b). According to the ZCLV method, the recording pit length varies at a predetermined rate within each zone Z as shown in FIG. 4(c), and hence the sector length also varies at a predetermined rate within each zone.
The CAV method employs a data recording format as shown in FIG. 5. More specifically, the sectors of all the tracks T on the disk are radially aligned and arranged in a radial pattern such that the length of each sector increases toward the outer periphery of the disk.
In this method, as shown in FIG. 6(a), the rotational speed of the disk is constant. Further, as shown in FIG. 6(b), the data recording apparatus holds the data rate at a constant level regardless of the radial position of the pickup device. According to the CAV method, as shown in FIG. 6(c), the recording pit length increases toward the outer periphery of the disk, and the sector length is also increased toward the outer periphery of the disk.
The CLV method has the highest recording density of the three. Therefore, assuming that disks having an identical size are used for recording by the respective methods, a CLV disk has the largest storage capacity. The ZCLV method is advantageous in that it provides a large storage capacity, like the CLV method, and in that the rotational speed of the disk-driving motor can be relatively easily controlled. The recording density of the ZCLV disk is between that of the CLV disk and that of the CAV disk. The recording density of the CAV disk is the lowest of the three.
In CD-R, DVD-R and similar disks, data is recorded by the CLV method or the ZCLV method for higher recording densities.
In a data recording apparatus using the CLV method or the ZCLV method, to increase the recording speed, it is required to increase the rotational speed of the disk. However, in the CLV method, it is required to quickly vary the rotational speed of the disk to seek a sector radially remote from a certain (present) position on the disk. Therefore, the driving torque of the disk-driving motor must be sufficient, which results in not only an increase in size of the motor but also an increase in electric power consumption.
In a data recording apparatus using the CAV method, since the disk is rotated at a constant speed, it is easy to increase the recording speed. Further, the data recording apparatus uses a motor having a small driving torque. Therefore, one might think that if a disk formatted by the CLV method or the ZCLV method is rotated at a constant speed for recording by the CAV method, it would be possible to improve the writing speed and reduce the size of the motor and the electric power consumption.
However, even if data recording is performed by the CLV method or the ZCLV method on a disk being rotated at a constant speed, CAV data is recorded on the disk, which makes it impossible for the other disk apparatus to properly read the data. That is, it is impossible to record CLV or ZCLV data on a disk that is controlled according to the conventional CAV method.
It is an object of the invention to provide a data recording apparatus that accurately records CLV or ZCLV data on a recording medium while rotating the recording medium based on the CAV method.
In a first aspect of the present invention, a data recording apparatus is provided that supplies data recorded on a recording medium, which is rotated by a motor, to a pickup device. The pickup device generates position information indicating the position of the pickup device with respect to the recording medium. The apparatus includes a recording control circuit that controls the motor such that the recording medium is rotated in a manner compliant with a constant angular velocity (CAV) method and controls an output rate of the data supplied to the pickup device based on the position information such that the data is recorded on the recording medium in a manner compliant with a constant linear velocity (CLV) method.
In a second aspect of the present invention, a data recording apparatus is provided that supplies data recorded on a recording medium, which is rotated by a motor, to a pickup device. The pickup device generates position information indicating the position of the pickup device with respect to the recording medium. The apparatus includes a recording control circuit that controls the motor such that the recording medium is rotated in a manner compliant with a constant angular velocity (CAV) method and controls an output rate of the data supplied to the pickup device based on the position information such that the data is recorded on the recording medium in a manner compliant with one of a constant linear velocity (CLV) method and a zone constant linear velocity (ZCLV) method.
In a third aspect of the present invention, a data recording apparatus is provided that supplies data recorded on a recording medium, which is rotated by a motor, to a pickup device. The pickup device generates position information indicating the position of the pickup device with respect to the recording medium and reads a wobble signal having a predetermined frequency from the recording medium. The apparatus includes a variable gain amplifier that receives the wobble signal from the pickup device and generates an amplified wobble signal having a constant amplitude. A recording control circuit controls the motor such that the recording medium is rotated in a manner compliant with a constant angular velocity (CAV) method and controls an output rate of the data supplied to the pickup device based on the position information and the predetermined frequency of the amplified wobble signal such that the data is recorded on the recording medium in a manner compliant with one of a constant linear velocity (CLV) method and a zone constant linear velocity (ZCLV) method.
In a fourth aspect of the present invention, a disk apparatus is provided that includes a motor for rotating a recording medium and a pickup device for recording data on the recording medium. The pickup device generates position information indicating the position of the pickup device with respect to the recording medium. A data recording device is connected to the motor and the pickup device, controls the motor such that the recording medium is rotated in a manner compliant with a constant angular velocity (CAV) method, and controls an output rate of the data supplied to the pickup device based on the position information such that the data is recorded on the recording medium in a manner compliant with a constant linear velocity (CLV) method.
In a fifth aspect of the present invention, a disk apparatus is provided that includes a motor for rotating a recording medium and a pickup device for recording data on the recording medium. The pickup device generates position information indicating the position of the pickup device with respect to the recording medium. A data recording device is connected to the motor and the pickup device, controls the motor such that the recording medium is rotated in a manner compliant with a constant angular velocity (CAV) method, and controls an output rate of the data supplied to the pickup device based on the position information such that the data is recorded on the recording medium in a manner compliant with one of a constant linear velocity (CLV) method and a zone constant linear velocity (ZCLV) method.
In a sixth aspect of the present invention, a method is provided that supplies data to a pickup device and records the data on a recording medium. First, position information indicating the position of the pickup device with respect to the recording medium is generated. Then, the recording medium is rotated in a manner compliant with a constant angular velocity (CAV) method. An output rate of the data supplied to the pickup device is controlled based on the position information such that the data is recorded on the recording medium in a manner compliant with a constant linear velocity (CLV) method.
Other aspects and advantages of the invention will become apparent from the following description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the invention.